Field
The example embodiments described hereafter relate generally to improvements in wheelbarrows and more particularly, but not by way of limitation, to a wheelbarrow in which the structural shape of the frame and/or positioning of the wheel thereof provide a wheelbarrow which distributes load favorably from the user to the machine, thus reducing the lifting force required.
Related Art
Reference to the prior art herein is not to be taken as an acknowledgement that such prior art constitutes common general knowledge in the art.
Wheelbarrows have been in widespread use for many years for the transportation of loads from one site to another over relatively short distances. Wheelbarrows of different design and configuration comprise a load carrying container supported by a frame having two handles for lifting and pushing, one or two wheels mounted at the front of the container extending downwardly therefrom, and two legs at the rear of the container, also extending downwardly therefrom. When the wheelbarrow is stationary, balancing and stability is maintained by the two rear legs and the one or two front wheels.
The two handles allow the wheelbarrow's supports to be raised from the ground in order to change from the stationary position to the mobile position. In the mobile position, only the wheel is in contact with the ground surface, whilst the operator's legs transfer the balance of the vertical load down and away.
There are a number of drawbacks associated with these conventional wheelbarrows. The single wheel facilitates the manual handling of the load, but the materials carried in the container frequently shift position therein and the balance of the wheelbarrow shifts, making control of the wheelbarrow quite difficult. As a consequence, operation of the normal presently available wheelbarrow by a person of relatively small stature may be extremely difficult, and indeed, even relatively large and powerful persons may encounter difficulties in manipulation of a heavily loaded wheelbarrow. To lift a loaded wheelbarrow, a substantial lifting force is required that depends on the actual load, the position of the center of gravity (CoG) with respect to distance between the CoG and the wheel axle, and on the distance between the handles and the wheel axle, as they are defined by established equations of the lever.
Patent DE20109039 describes a wheelbarrow wherein the bin has a recess for receiving a portion of the wheel, allowing the bin to saddle the wheel. This design has the effect of lowering the floor of the bin and therefore lowering the center of gravity. While this assists in improving the stability of the wheelbarrow it does not assist in reducing the force required to tilt and unload the wheelbarrow, in fact making it more difficult to unload the barrow. Furthermore, when the load is a slurry or is granular, the portion saddling the wheel will deflect inwardly towards the wheel and can result in friction upon the wheel. To ensure this does not happen the portions of the bin saddling the wheel require an additional frame structure which adds weight to the wheelbarrow. Furthermore, as the wheel is partially enclosed, mud, concrete and other debris will eventually accumulate therein, dry and cause friction upon the wheel. As the wheel is partially enclosed it would be difficult to clean this area without having to remove the wheel.